Manufacture of filaments and fibers



during spinning.

Patented Mar. 26, 1946 UNITED STATES PATENT orncs 2,397,338 MANUFACTURE or FILAMENTS AND mans Hale Cowling, Chester, Pa., assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Application October 12, 194 3, Serial No. 505,929

12 Claims.

This invention relatesto the manufacture of films, filaments and the like by extruding solufilms and the like to insure that products of uniformly high quality are obtained. Other objects of the invention will be apparent from the description hereinafter.

The process and spinning solution of this invention may be employed in the formation of filaments, films and the like but it will be described hereinafter with relation to the spinning of filaments because its advantages in this connection are more pronounced.

Various assistants have heretofore been found which improve spinnin conditions by reducing clogging of the orifices in the spinnerets and reducing the tendency of the filaments to break Among the compounds su gested for this purpose are various cation-active compounds, an example of which is lauryl pyridinium chloride. Ethylene oxide polymers having molecular weights between 1.500 to 5,000 have also been used. While these compounds have been suggested to be used in the viscose spinning solutions or in the spinning baths used therewith as well as in both, they actually are ineffective when used only in the spinning solution. This is readily explained in the case of thecation- 'active compounds by the fact that they are simply unstable and are rapidly decomposed in the alkaline conditions prevailing in the viscose spinning solutions. The ineffectiveness of the ethylene oxide polymers, on the other hand, is a fact the reasons for which are not understood.

It has'now been found that certain high molecular weight polymers of ethylene oxide are surprisingly effective when incorporated in the viscose. This is quite unexpected in view of the ineffectiveness of the lower molecular weight polymers heretofore suggested when used-in the viscose solutions. It is the more remarkable fOl the reason that these high molecular weight polymers of ethylene oxide have as compared to the. low molecular weight polymers relatively low effectiveness when used in the coagulating or pre cipitating baths. When used in the spinning baths, the high molecular weight polymers are rapidly exhausted apparently. by absorption on the filaments and must be so frequently replenished that their use is entirely impractical.

The polymers of ethylene oxide which have been found to operate when incorporated in the viscose solutions in accordance with this invention are those having molecular weights of the order of 6,000 to 9,000 or higher. The molecular weights herein specified are those obtained in accordance with the following formula:

112,200 Hydroxyl number wherein the term hydroxyl number has its usual meaning, viz. the number'of milligrams of potassium hydroxide necessary to'neutralise the acetic acid obtained by the saponification of the acetylated compound from one gram of sample. The method for determining hydroxyl number is described by Smith and Bryant, in the Journal of the American Chemical Society, Volume 57, page 61 (1935) and by Smith, Bryant and Mitchell in the same Journal, Volume 62, page 1 (1940) The above formula is derived from consideration of the fact that 112,200 r'nilligrams'of potassium hydroxide are equivalent to one gram molecular weight of a dihydric alcohol. The

Molecular weight:

molecular weights specified herein are not to be confused with the arbitrary designations heretofore attached to commercial ethylene oxide polymers. Thus, a lot of'ethylene oxide polymer commercially known as Carbowax 4,000 was found to have a molecular weight of about 3,000

and another lot of ethylene oxide polymer designated as Carbowax 6,-000was found to have a molecular weight of 8,400 when determined by the above method. 7

The high polymers are water-soluble, nonionogenic, solids and are effective to improve spinning conditions when they are incorporated in the viscose in proportions as low as of the order of 0.01%, though more or less may be used if desired.

Spinning viscoses containing these high ethylene oxide polymers improves the quality of the of spinning solution through the orifice in the range of 0.5:1 to 2:1 or higher. This tendency to break apparently is present under such spinning conditions regardless of the presence or absence of deposits within the spinneret orifice, and the high polymer of ethylene oxideapparently counteracts it by favorably influencing the process of setting or coagulation of the viscose mass as it leaves the orifices.

Besides reducing the tendency of the extruded viscose to break while undergoing the incipient stages of coagulation, the high polymers of ethylene oxide improve uniformity of the filaments by greatly reducing the tendency toward formation of cellulose rings or other deposits within the orifices. This tendency to clog is particularly pronounced when spinning is performed into baths containing zinc salts, especially if they are present in high concentrations of 3 to When this clogging of some of the orifices is complete,-

it reduces the total number of filaments in the bundle issuing from a given spinneret and tends to make the remaining filaments somewhat larger in diameter than would be the case where no clogging of any of the orifices of the spinneret occurs. Where a number of the holes or orifices in the spinneret are only partially clogged, the result is a mixture of filaments of various sizes issuing from the spinneret. In addition, the fila- -mentary bundle issuing from a given spinneret which is subject to clogging varies in uniformity along its length depending upon the fluctuation in the extent of clogging in individual orifices, the rapidity of clogging, as well as the completeness of clogging of anyof the orifices in the spinneret. The result is a filamentary yarn having considerable non-uniformity within a given cross-section as well as along its length,

The following examples are illustrative of the invention: a

Example 1 Example 2 A viscose solution containing 0.01% of a polymer of ethylene oxide having a molecular weight of 8,400 was extruded with a Jet stretch ratio of While preferred embodiments of the invention have been disclosed, it is to be understood that changes and variations may be made without departing from the spirit and the scope of the invention as defined by the appended claims.

I claim:

1. In the method of producing artificial filaments, films and the like, the step of extruding a solution of viscose containing dissolved therein a small proportion of an ethylene oxide polymer having a molecular weight of at least 6,000

2:1 into a spinning bath containing from 7 to 8% sulphuric acid, about 14% sodium sulphate, about 1% zinc sulphate, and about 5% glucose.

1 Example 3 1 A viscose solution containing 0.01% of'a polymer of ethylene oxide having a molecular weight of about 6.000 was extruded into a spinning bath containing 9% sulfuric acid, 20% sodium sulfate and 3% zinc sulfate. 7

The application of the high polymer 'of eththrough a jet into an aqueous precipitating medium, the molecular weight and the proportion of the polymer being such that breakage of filaments and encrustation of the Jet are inhibited during the product-forming stage.

. 2. In the method of producing filaments, films and the like, the step of extruding a solution of viscose containing dissolved therein a small proportion of an ethylene oxide polymer having a molecular weight ofv at least 6,000 through a jet into an aqueous acid precipitating medium, the proportion of the polymer being such that breakage of filaments and encrustation of the Jet are inhibited during the product-forming stage.

3. In the method of producing filaments, films and the like, the step of extruding a solution of viscose containing a small proportion of an ethylene oxide polymer having a molecular weight of about.8,400through a jet into an aqueous precipitating medium, the proportion of the polymer being such that breakage of filaments and encrustation of the jet are inhibited during the product-forming stage.

4. In the meth'od of producin filaments, films and the like, the step of extruding a solution of viscose containing a small proportion of an ethylene oxide polymer having a molecular weight of about 6,000 through a jet into an aqueous acid precipitating medium containing a zinc salt, the proportion of the polymer being such that breakage of filaments and encrustation of the Jet are inhibited during the product-forming stage.

5. In the method of producing filaments, films and the like, the step of extruding a solution of viscose containing a small proportion of an ethylene oxide polymer having a molecular weight of about 8,400 through a Jet into an aqueous acid precipitating medium, the proportion of the polymer being such that breakage'of filaments and encrustation'of the jet are inhibited during the product-forming stage.

ylene oxide in accordance with the present in vvention has the advantage of placing it right at the point of greatest usefulness-in thematerialpassing through the orifice-so that it can be most effective in the lowest concentration. The

small amount used apparently stays mostly in the filaments formed since it has been found to have no detrimental effect upon the spinning bath and the circulating equipment for maintaining the concentration of the bath. The lower polymers heretofore used could not satisfactorily be used in baths containing sugars since they caused the formation of gummy precipitates which collected in the return pipes and fouled them.

a 6. In the method of producing filaments, films and the like, the step of extruding a solution of viscose containing a small proportion of an ethylene oxide polymer having a molecular weight of about 8,400 through a jetinto an aqueous acid precipitating medium containing a zinc salt, the proportion of the polymer being such that breakage of filaments and encrustation of the jet are inhibited during the product-forming stage.

'7. .A viscose solution containing dissolved therein a small amount of an ethylene oxide polymer having an average molecular weight of at least 6,000, the molecular weight and the amount of the polymer being such that breakage of filaments and encrustation of the jet are inhibited during the product-forming stage.

8. A viscose solution containing a small amount of ethylene oxide polymer having an average molecular weight of about 8,400, the amount of. the polymer being such that breakage of filaments and encrustation of the jet are inhibited during the product-forming stage.

9. In the method of producing filaments, films and the like, the step of extruding a solution of viscose containing a small proportion of an ethylene oxidepolymer having a molecular weight of the order 01' 6000 to 9000 through a jet into an aqueous acid precipitating medium, the proportion of the polymer being such that breakage of filaments and encrustation of the Jet are inhibited during the product-forming stage.

10. In the method of producing filaments, films and the like, the step of extruding a solutionxot viscose containing of the order of 0.01% or an ethylene oxide polymer having a molecular weight of the order of 6000 to 9000 through a jet into an aqueous acid precipitating medium.

11.- A viscose solution containing a small amount of ethylene oxide polymer having an average molecular weight of the order of 6000 to 9000, the amount of the polymer'being such that break: age of filaments and encrustation of the jet are inhibited during the product-forming stage.

12. A viscose solution containing of the order of 0.01% ethylene oxide polymer having an average molecular weight or the order of 6000 to 9000.

HALE COWLING. 

